Answer:
Explanation:
Force of friction acting on the body = μ mg cosθ
= .4 x 70 x 9.8 x cos30
= 237.63 N
component of weight = mgsinθ
= 70 x 9.8 x sin30
= 343 N
Net upward force = 600 - mgsinθ - μ mg cosθ
= 600 - 343 - 237.63
= 105.37 N
acceleration in upward direction = 105.37 / 70
= 1.5 m /s²
s = ut + 1/2 a t²
= 0 + .5 x 1.5 x 3²
= 6.75 m .
The short answer is that the displacement is equal tothe area under the curve in the velocity-time graph. The region under the curve in the first 4.0 s is a triangle with height 10.0 m/s and length 4.0 s, so its area - and hence the displacement - is
1/2 • (10.0 m/s) • (4.0 s) = 20.00 m
Another way to derive this: since velocity is linear over the first 4.0 s, that means acceleration is constant. Recall that average velocity is defined as
<em>v</em> (ave) = ∆<em>x</em> / ∆<em>t</em>
and under constant acceleration,
<em>v</em> (ave) = (<em>v</em> (final) + <em>v</em> (initial)) / 2
According to the plot, with ∆<em>t</em> = 4.0 s, we have <em>v</em> (initial) = 0 and <em>v</em> (final) = 10.0 m/s, so
∆<em>x</em> / (4.0 s) = (10.0 m/s) / 2
∆<em>x</em> = ((4.0 s) • (10.0 m/s)) / 2
∆<em>x</em> = 20.00 m
Find the intensity of the electromagnetic wave described in each case.
(a) an electromagnetic wave with a wavelength of 645 nm and a peak electric field magnitude of 8.5 V/m.
(b) an electromagnetic wave with an angular frequency of 6.3 ✕ 1018 rad/s and a peak magnetic field magnitude of 10−10 T.
Newton’s Thrid Law, which states that for every reaction there is an opposite reaction.
